Regenerative heat exchanger with moveable matrix



Dec. 1, 1959 e. LANGE 3 3.

REGENERATIVE HEAT EXCHANGER wrm MOVEABLE MATRIX Filed April 24, 1956 2 Sheets-Sheet 1 WWW/WW INVENTOR GUNTHER LANGE ATTORNEYS Dec. 1, 1959 A G. LANGE REGENERATIVE HEAT EXCHANGER wrm MOVEABLE MATRIX 2 Sheecs-Sheet 2 mm Aprll 24, 1956 v GUNTHER LANGE grill/471 7 ii 111 INVENTOR it' /mi 4.5%? all/z! ATTOR N EYS REGENERATIVE HEAT EXCHANGER WITH MOVEABLE MATRIX Giinther Lange, Munich, Germany, assignor to BMW Triebwerkbau Gesellschaft mit bescliraenkter Haftung This invention relates to regenerative heat exchangers, preferably of the counter-current type, with moveable matrix. Regenerators of this type are advantageously used in all applications where it is desired to transfer heat from a hot to a cooler medium, for example from hot exhaust gases to cooler air, as is the case in furnace installations, gas turbines, and the like. i

In regenerative heat exchangers having a moveable matrix comprising chambers filled with wire mesh or the like, lheavy transfer losses are encountered due to the compressed air contained in the flow passages of the movea'blematrix being carried over from the air side to the gas side. Moreover, there are leaking losses due to leakages at the sealing faces between air side and gas side along the surface of the heat exchanger matrix. These leakages increase in proportion with the length of the sealing joints and with the distortion caused by heat stresses. Undesirable accumulation of deposits on the surface of the heat exchanger matrix is encountered already after a relatively short time of operation, which results in reduced efliciency of the heat exchanger and in a pronounced increase of pressure losses. In consideration of the possibility of deposit accumulation, the reduction of the hydraulic diameter and consequently the increase of the coeflicient of heat exchange, must be limited.

There are other types of regenerative heat exchangers in which the rotating matrix consists of individual discs separated by spacers, the discs and the spacers being arranged 'on a common shaft and kept under lateral pressure, the shaft imparting rotational movement to the discs. Slots in the separating wall'between the gas spaces allow the passage of the discs, the edges of these slots serving at the same time as a seal between the two heat exchanging media. Due to the individual sealing of each disc, the entire sealing length increases enormously, which results in high friction losses. With small hydraulic radiai.e. small distances between two adjacent discs for obtaining high coefficients of heat exchange with small pressurejlossest he sealing elements of the separating wall are reduced to thin sheet metal strips which cannot be realized in practice. Consequently, in these known types of heat exchangers, the coeflicient of heat exchange is: limited by considerations of practicability.

Moreover, regenerative heat exchangers have been proposed the heat exchanging matrix of which consists of two stacks of annular lamellae which rotate in opposite directions. Sealing in the plane of separation between the air side and the gas side is accomplished by means of spacing discs which are arranged at both sides of the axis of rotation of the matrix, a spacing disc being disposed between each adjacent pair of lamellae, and the lamellae and spacing discs being urged into face sealing contact with each other by elastic means. This form of construction also entails considerable friction which can be substantially reduced by the apparatus according to the invention, a substantial reduction of the length of the sealing joints being achieved at the same time.

The present invention avoids the drawbacks of the States Patent ice known devices by using a plurality of stacked annularlamellae which in the separating plane between the heat exchanging media, for example, air and gas, are urged into air-tight face sealing contact with each other, thefree flow passages between the lamellae being maintained on both air and gas sides by one or more rows of spacing members.

According to another feature of the invention, the annular lamellae are guided only in the zone of separation between the gas spaces, for example by means of cylindrical rolls guiding them in radial direction, and by pairs of tapered rollers guiding them in axial direction, the guiding members serving at the same time for sealing the two gas spaces against each other.

'By compressing the individual annular lamellae into an air-tight stack in the plane of separation between the two gas spaces, the heat emitting medium contained in the spaces between the lamellae is squeezed out, thus preventing the transfer thereof to the heat absorbing side of the heat exchanger. By this arrangement transfer losses are completely avoided. Due to the fact that all of the lamellae rotate in the same direction and at the same speed, there is no friction between the lamellae. The necessary length of the sealing joints is reduced to a minimum and is equal to the circumference of the cross sectional area of the compressed lamellae. The use of rolls as sealing elements makes it possible to apply a contact pressure of any desired magnitude dueto the fact that there is neither the possibility of frictional losses nor of wear of the sealing elements.

After having passed through the sealing zones, the

lamellae are spread apart on both gas sides in order to maintain the free flow passages between the lamellae necessary for the passage of the heat exchanging media. This spreading of the lamellae is effected by the spacing members which at the same time serve for the continuous automatic cleaning of the surfaces of the heat exchanger matrix. The spacing members are combined into comb structures, at least one of such structures covering the entire depth of the rotating lamellae on each side of the axis of rotation of the matrix.

' Further objects and features of the invention will become apparent from the following description of an embodiment of the invention which is given by way of example only, and is described with reference to the accompanying drawings in which Fig. 1 shows a regenerative heat exchanger according to the invention in longitudinal section along line I-I of Fig. 2;

Fig. 2 is a cross-sectional view taken along line II-II of Fig. l and Fig. 3 is a horizontal sectional view of the heat exchanger taken along line III-Ill of Fig. 2.

The housing 1 of a regenerative heat exchanger is subdivided into an air space 3 and a gas space 4 by means of a separating wall 2. Each of these spaces is provided with two connecting flanges, the flange 13 of air space 3' constituting the inlet for the cool air and flange 14 of that space being the outlet for the heated air, while flange 15 of gas space 4 is the inlet for the hot gases and flange 16 of the same space is the outlet for the cooled gases. A rotatable heat exchanging matrix 5 composed of a plurality of stacked annular lamellae 6 is provided within the housing 1 wherein it extends through both spaces 3 and 4 and surrounds the separating wall 2. This rotatable stack of lamellae is guided, respectively centered, only in the plane of separation between the spaces 3 and 4, radial location being provided by cylindrical rolls 8 and 9 and axial location being effected by means of tapered rollers 7. Rotational movement is imparted to the stack of lamellae by means of rolls 9 which are formed as gears the teeth of which are in meshing engagement with corresponding teeth provided on the inner circumference of the annular lamellae. The drive shafts 9a of the toothed rolls 9 are extended outside of the housing and may be drivingly connected with each other, for example, by means of a chain or belt drive 9b as shown in Figure 3. One of the shafts, for instance, shaft 9a, may be driven from a suitable source of power through appropriate transmission means such as a belt drive 90, as also shown in Figure 3.

In order to avoid transfer and leakage losses, the spaces 3 and 4, in which prevail different pressures, must be sealed in the zones of passage of the lamellae stack. Transfer losses, i.e. losses caused by the transport of one of the media from one space into the other via the heat exchanging matrix, are avoided by compressing the individual lamellae into'air-tight face sealing contact with each other in the plane of separation between the two spaces. For this purpose at least one of the tapered rollers on each side is resiliently mounted, forexample by subjecting it to the action of a spring. Sealing of the lamellae stack against leakage losses is effected by means of the guide rolls 8 and the toothed rolls 9, together with the tapered rollers 7.

After the stack of lamellae has passed through the sealing zone, the free flow passages between the lamellae 6 necessary for the passage of the heat exchanging media are created by spreading the lamellae apart. For this purpose one or more rows of spacing members 11 are provided on the air side as Well as on the gas side. Each row of spacing elements 11 is combined into a comb structure 12. At least one of the comb structures 12 provided on either side extends over the entire depth of the lamellae 6 for the purpose of cleaning the surfaces thereof.

I claim:

1. A regenerative heat exchanger provided with a plurality of separate fluid-flow passages therethrough having a rotatable heat exchanging matrix consisting of individual annular lamellae independent of each other and forming a stack of lamellae, means for urging said annular lamellae into tight face-to-face contact with each other at mutually spaced locations in the plane of separation between said fluid-flow passages, means including cylindri cal rollers in said plane of separation for guiding and centering said lamellae in a radial direction thereof, and at least one row of spacing members in each of said fluid passages for maintaining free flow passage between said lamellae.

2. A regenerative heat exchanger according to claim 1, wherein said heat exchanger is of the counter-flow type.

3. A regenerative heat exchanger according to claim 1, wherein said stack of annular lamellae is guided only in the two zones of separation between said flow passages.

4. A regenerative heat exchanger provided with a plurality of separate fluid-flow passages therethrough having a rotatable heat exchanging matrix consisting of individual annular lamallae independent of each other and forming a stack of lamellae, means for urging said annular lamellae into face-to-face contact with each other at mutually spaced locations only in the plane of separation between said fluid-flow passages, at least one row of spacing members in each of said fluid passages for maintaining free fiow passage between said lamellae, said means including cylindrical rollers for guiding and centering said lamellae in a radical direction and at least two pairs of tapered rollers for keeping said lamellae face to face with each other in an axial direction, said rollers serving at the same time as sealing means between said fluid-flow passages.

5. A regenerative heat exchanger according to claim 4 wherein the inner circumferential surfaces of said annular lamellae are provided with tooth means and wherein one or more of said cylindrical rollers are provided with tooth means, said tooth means being in meshing engagement with the tooth means of said lamellae.

6. A regenerative heat exchanger according to claim 5 wherein said rollers are mounted on shafts, and further comprising driving means for said toothed rollers'for effecting rotation of said lamellae, said toothed rollers being drivingly connected with each other.

7. A regenerative heat exchanger according to claim 4 wherein the outer circumferential surfaces of said annular lamellae are provided with tooth means.

8. A regenerative heat exchanger according to claim 4, wherein said tapered rollers are resiliently mounted at least on one side of said stack of lamellae.

9. A regenerative heat exchanger according to claim 1,

wherein each row of spacing member comprises a comblike structure and wherein the teeth of at least one of said spacing members in each of said flow passages extend over the entire depth of said lamellae. I

10. A regenerative heat exchanger provided with a plurality of separate fluid-flow passages therethrough having a rotatable heat exchanging. matrix consisting of individual annular lamellae independent of each other and forming a stack of lamellae, means for urging said annular lamellae into tight face-to-face contact with each other at mutually spaced locations between said fluid passages, means at said mutually spaced locations for guiding and centering said lamellae in a radial direction thereof, and at least one row of spacing members in each of said fluid passages for maintaining free flow passages between said lamellae.

References Cited in the file of thispatent UNITED STATES PATENTS Schofield May 18, 1875 

